In general, a method of using an acid, a method of using enzymes such as α-amylase, β-amylase and glucoamylase are made available as a method of producing the starch sugar such as dextrin, maltose, glucose.
However, these methods have been problems that a manufacturing facility become a very large scale, and thereby occurring a problem of an installation location, and requiring a large amount of water, steam and electricity, and a manufacturing cost become very high. Further, these starch sugar were made by using a starch of a raw material wherein the protein was preliminarily removed, and were produced under the conditions that it does not contain an amino acid which has significance and includes highly nutritious components.
On the other hand, except for these methods of production, for example, “a method of producing rice glycosylation liquid” of Mar. 11, 2005, is known wherein the method can accelerate a hydrolysis under high pressure (Patent Literature 1).